Vitali Klitschko was scheduled to defend his WBC title against Hasim Rahman on Nov. 12 in Las Vegas. Unfortunately, the fight was canceled because Klitschko suffered a knee injury during a recent sparring session. Because of his injury, Klitschko underwent surgery on Tuesday in Southern California.

The operation was done by Dr. Neal Elattrache, Director of the Sports Medicine department at the Kerlan-Jobe Clinic, in Inglewood, Calif. Dr. Elattrache treated a new rupture in the torn anterior cruciate ligament (ACL) and damage to the medial meniscus on Klitschko’s right knee.

“The surgery took 1Â½ hours and was a complete success, but Vitali cannot compete in professional sports for the next six months,” said Dr. Elattrache. “With this severe an injury it would have been absolutely impossible for Vitali to participate in a fight in the near future. The knee was totally unstable and it would have not held up.

Said Vitali: “Lately, I have been spending more time with my injuries than with my opponents inside the ring. The decision to retire from professional sports was a very difficult one, one of the hardest I have ever had to make. I love boxing and am proud to be the WBC and RING heavyweight champion.

“But I would like to end my career at its peak so I am retiring now as the champion to clear the way for my successors. I would like to take this opportunity to thank again the WBC, especially President Jose Sulaiman, my team, the media and all my fans for the many years of cooperation and support. In the future, I plan to get more heavily involved and devote more energy to tackling social and socio-political challenges in my native Ukraine.”